Attention is currently required from: Julius Werner, Nick Vaccaro, Yu-Ping Wu.
Vladimir Serbinenko has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/81508?usp=email )
Change subject: Support for creating hybrid vboot images ......................................................................
Patch Set 5:
(1 comment)
Patchset:
PS5:
I'm honestly not really sure what you're trying to do here anyway. […]
My goal is to dual-boot between UEFI (or other payload) and normal ChromeOS. Limitations: 1) RW needs to stay the same as changing it would break ChromeOS mechanism 2) Moreover ChromeOS may have requirements on coreboot so that it's advantageous to continue using unmodified RW to avoid breakage 3) Without some changes to ACPI and implementation of SMMSTORE some OS including Windows will not install at all and some may exhibit shortcomings (I think I had some but I don't use RW_LEGACY any longer) 4) FMAP layout can't be modified because of both RW and update requirements
RO, on the other hand, can be modified after unlock. I understand payload phylosophy but here 2 scenarios of booting have contradictory requirements on ramstage: 1) Windows (and few other OS) need improved ACPI and SMMSTORE 2) ChromeOS needs coreboot not to change
This is more akin to CMOS bootblock philosophy of switching between r[oa]mstage. Ans also akin the idea of using whatever space is available. We really have only 2 places to put alternative r[oa]mstage: RW_LEGACY and RO_COREBOOT. Former is tight on space. Hence the design proposed in those patches. I believe this configurable hack could be of value to chrultrabook community where "How to multiboot ChromeOS and Windows" is a common request